1. Field of the Invention
The present invention relates to a water pollution evaluating system for evaluating the pollution of water stored in a reservoir such as a pool, bath, cooling tower, fish raising vessel and the like.
2. Description of the Related Art
As a method of evaluating the pollution of water stored in a reservoir such as a pool, bath, cooling tower, fish raising vessel and the like, a COD component which is mainly water soluble organic matters in water has been measured and the pollution of the water has been evaluated by the increase or decrease of the COD value thereof.
Recently, it has been recognized that it is important to manage and regulate the water stored in the reservoir such as the pool, bath, cooling tower, fish raising vessel and the like so that the water is maintained in a clean state. Thus, attention has been paid to a method of sterilizing and purifying water using hypohalogenous acid having a sterilizing and purifying capability which is slightly contained in the water or produced by electrolyzing the water by adding a suitable amount of chlorine ion or bromine ion to the water.
In the water stored in the reservoir such as the pool, bath, cooling tower, fish raising vessel and the like, when the concentration of the hypohalogenous acid produced by electrolysis is higher than a suitable concentration, it may aversely affect human bodies, raised fishes, equipment and the like which are in contact with the water and rough skin, death, corrosion and the like may be caused thereto by the hypohalogenous acid; whereas when the concentration of the hypohalogenous acid produced by the electrolysis is not sufficient, there arises a problem that the water is not sufficiently sterilized and purified so that a water passage is clogged by the occurrence of diseases, waterweeds and the like and a heat efficiency is lowered. Accordingly, the production of the hypohalogenous acid must be properly controlled in accordance with a degree of pollution of water.
Incidentally, as a method of measuring the COD as an index of the pollution of waters there has been employed a method wherein a portion of water to be measured is collected in a suitable amount; potassium permanganate is added to the water as an oxidizing agent under prescribed conditions; the amount of the potassium permanganate consumed to oxidize a COD component is measured by titration; and the pollution of the water is calculated by converting the amount of consumed potassium permanganate into the amount of oxygen. In the conventional method, however, not only is a long time required to take the measurement but also the measurement is complex because the water must be collected as necessary and the above procedure must be carried out. Accordingly, there has been desired a system capable of promptly and simply evaluating a COD value as an index of the pollution of water in an apparatus in order to control the production of the hypohalogenous acid as described above.
An object of the present invention made in view of the above problem is to provide a water pollution evaluating system capable of promptly and simply evaluating the polluted state of water as a COD value.